Multistage Compressor Heat Recovery via Rankine Cycle
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Solution Overview
Problem
Compressor devices face inefficiencies due to heat generation during gas compression, which is difficult to manage, especially in industrial settings where interaction times are short, and existing heat recovery methods do not significantly improve compressor efficiency.
Innovation Solution
A multi-stage compressor device with a high-pressure screw compressor element driven by a motor and a low-pressure centrifugal compressor element driven by an expander in a closed power cycle, utilizing a Rankine cycle process to efficiently recover and reuse the compressed gas's heat, allowing for independent optimization of each compressor element and improved overall efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If liquid coolant is injected into the compressor element to limit heat generation, then heat management is improved, but the interaction time is too short for the positive influence to be pronounced
Solution Approach 1:
The patent introduces a separate cooling circuit with coolant channels as an intermediary system between the compression chambers and the compression element. This mediator allows heat transfer without requiring direct contact between coolant and compression elements, thereby providing effective cooling even with very short interaction times during compression cycles.
Solution Approach 2:
The cooling channels are pre-positioned within the compression element structure, and coolant is circulated through these channels in advance of and during the compression process. This preliminary preparation of the cooling system ensures that heat removal is continuously effective without being limited by the short duration of each compression stroke.
2Device complexity
If compressor elements are mechanically linked to the motor for direct drive, then power transmission is simplified, but the choice of components is restricted and they cannot be optimized independently
Solution Approach 1:
The patent divides the compression system into separate compression elements (first compression element and second compression element) that are not mechanically linked to each other or to the motor. Each compression element operates independently with its own cooling circuit, allowing them to be optimized for different functions (e.g., different pressure ranges, different cooling requirements) without being constrained by a common mechanical drive system.
Solution Approach 2:
The patent introduces a common coolant distribution system as an intermediary that serves multiple independent compression elements. This mediator allows the compression elements to remain mechanically independent while still providing coordinated cooling through shared coolant supply and temperature monitoring, achieving both independence and system integration.
3Loss of energy
If heat is recovered from compressed gas using a turbine mechanically linked to the motor, then overall efficiency is improved, but the efficiency of the compressor device itself is not improved and component choice is restricted
Solution Approach 1:
The patent uses a coolant circulation system as an intermediary to transfer heat from the compression process to a heat recovery system. The coolant absorbs heat from the compression chambers during compression, and this heated coolant then transfers energy to a turbine or other heat recovery device. This intermediary approach allows heat recovery without requiring direct mechanical linkage between the compressor and turbine, enabling independent optimization of both systems.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This configuration enhances compressor efficiency by decoupling the low-pressure compressor from the motor-driven high-pressure compressor, enabling separate speed adjustments and optimal component selection, resulting in improved energy utilization and reduced heat loss.
Implementation Method 1
utilizing a Rankine cycle process to efficiently recover and reuse the compressed gas's heat
Implementation Method 2
a heater which is made up of at least one heat exchanger through which at least part of the compressed gas flows
Implementation Method 3
the medium in the closed power cycle is pumped around by means of a pump
Implementation Method 4
a heater which is made up of at least one heat exchanger through which at least part of the compressed gas flows
Implementation Method 5
the gaseous medium which leaves the expander is liquefied again at low pressure in the condenser
Data Source
AI summary
An improved multi-stage compressor device for compressing gas, which compressor device (1) mainly consists of at least two compressor elements (2-5-28) placed in series one after the other, at least one of which (5-28) is driven by a motor (9), characterized in that at least one other compressor element (2) is driven separately, in other words without any mechanical link with said motor (9), by means of an expander (18) of a closed power cycle (12) with a circulating medium inside which is heated by the compressed gas.